Error: Program “/NDK-build” not found in PATH

Recently, I want to develop android applications with opencv. 

After downloaded opencv sdk and import to my eclipse, Some errors occurred.

One of them is Error: Program “/NDK-build” not found in PATH.

My OS is Ubuntu12.04, it is a linux environment, so i modified the Build command: ${NDKROOT}/ndk-build.cmd to ${NDKROOT}/ndk-build. The reason is that *.cmd is used for Windows version.

Second, in my Environment variables,  I don't have NDKROOT, so I add this variable and set the relative path to my ndk folder. 

As a result, Error: Program “/NDK-build” not found in PATH fixed.